What should we do? Two no-show/no-call situations were treated differently

Q. We have a strict rule against not calling in before a missed shift to report an absence. We require workers to make that call at least one hour before the shift is to start, unless they cannot do so due to an emergency. Otherwise we mark the absence as unexcused. Recently, an employee went to the emergency room and couldn’t make the call because she could not get cell service where she was and was undergoing triage treatment. We didn’t hold her to the rule. Now another employee, who heard from the first employee that she was excused, is complaining she’s being treated unfairly, but her situation was not the same. What do we do?